Hydro-foil attachment for boats



April 26, 1966 w, B w n- 3,247,820

HYDRO-FOIL ATTACHMENT FOR BOATS Filed Feb. 5, 1965 mveuroR WILLIAM B. WHITE Mid/ 1 M042 3,247,820 HYDRO-FOIL ATTACHMENT FOR BOATS William B. White, 798 Lampson St., Victoria,

. British Columbia, Canada Filed Feb. 5, 1965, Ser. No. 430,517 1 Claim. (Cl. 114-665) This invention relates to fins for boats and in particular to fins for increasing the planing efficiency of boats.

Another object of this invention is the provision of fins or hydro-foils which may be disposed edgeways along the underside of the boat on either side of its centre line so as to restrict the lateral flow of surface water therebeneath and to form a passage with the longitudinal flow of air so as to'enhance the planing qualities of the boat.

A still further object of this invention is to provide fins or hydro-foils for the purposes foregoing which may be adjustably positioned relative to the longitudinal axis of the boat.

A still further object of this invention is to provide a hydro-foil or fin which may be easily fixed to or removed from the boat when the latter is in the water so as not to serve as an impediment when it is desired to beach the boat or load the boat on a trailer.

A yet further object of this invention is to provide hydro-foils or fins of the above-described nature which are cheap to manufacture and which are capable of standardization for various makes and sizes of boats.

In the drawings which illustrate the embodiments of the invention,

FIGURE 1 is an end view of the stern of a boat showing one embodiment of the fin or hydro-foil aflixed thereto,

FIGURE 2 is a side view of the embodiment of FIGURE 1,

FIGURE 3 is an isometric view of the embodiment of FIGURES 1 and 2 with sections of the fin and its connecting assembly partially removed, and

FIGURE 4 is another View similar to FIGURE 1 in which an alternative embodiment of the invention is illustrated.

Referring to the drawings and particular to FIG- URES 1, 2 and 3 thereof, there is shown a boat which has a flat or warped bottom 11 and a square transom 12. This type of boat is normally capableof planing when driven by a motor of suitable size. However, as is well known with boats of this nature, the broad wetted surface of the boat creates considerable friction with the water over which it travels and thereby reduces the speed of the boat.

The planing attachment to which this invention is directed comprises a pair of fins 13 and 14 secured in a manner hereinafter to be described by a pair of gripping members 15 and 16, the latter being secured to the bottom 11 of the boat on either side of the latter center line and is close to the chines as the shape of the bottom permits. In describing the boat attachment, reference only will be made to fin 13 and gripping member 15 as the construction and placement of fin 14 and gripping member 16 is exactly the same. The fin 13 is formed from an elongated strip of stiff smooth metal, such as an aluminum alloy, the length of the strip being dependent upon the size, weight and shape of the boat. However, it is generally considered that the length of the fin shall be roughly half the length of the boat. This length ratio is not obligatory as it is dependent, as hereinbefore stated, upon the length, size and weight of the boat, and upon the power of the driving engine.

The fin is provided with a transversely extending flange 17 formed at one longitudinally extending edge '18 thereof, this flange may be formed by bending the strip at said edge or it may be molded as an integral part of the fin United States Patent 0 3,247,820 Patented Apr. 26, I966 and generally extends on either side of the fin so that the edge 18 of the latter assumes a T-shape when viewed in transverse cross section.

The fin 13 is bent along a longitudinal line as at 20 toan obtuse angle, generally in the nature of said line extending from end to end of the fin substantially midway between its flanged edge 18 and its other or lower edge 22 to form an upper leg portion 23 and a lower laterally extending foot portion 24. The flange 17 is provided with a row of longitudinally aligned holes 25 formed therethrough, the purpose of which will be hereinafter explained.

The gripping member 15 is preferably of rectangular cross sectional configuration and is somewhat longer than the fin 13. It may be of wooden construction or formed of the same material as the fin, has one side 30 shaped to fit the bottom 11 of the boat when said member is positioned thereagainst so as to extend in a fore and aft direction adjacent the chine thereof. The gripping member 15 is also formed having a T shaped way 32 extending from one end to the other and opening outwardly at its other or lower side 33 opposite its one side 30. This T-shaped way is of a size so that it will slidably yet snugly receive the T-shaped edge 18 of the flange 17 of the fin 13 when the two are aligned end to end. The

gripping member is secured as by screws 35 to the bottom' 11 of the boat in a fore and aft direction adjacent the chine thereof. The T-shaped way being disposed so that when the fin 13 is united with the gripping member 15, the leg portion 23 of the fin will extend vertically downwardly.

The gripping member 15 also has a short after portion locked against relative longitudinal sliding movement by,

means of a locking bolt 40 which is slidably mounted in gudgeons 42 for vertical movement, said locking bolt being located over the hole 38 in the after portion 37 of the gripping member, and having its lower end portion 43 suitably shaped for insertion through said lastmentioned hole and into and through any one of the holes 25 formed in the flange 17 of the fin. The locking bolt 40 may be provided at its upper end 44 with a handle 45, whereby said bolt may be vertically operated and, if it is desired, may be spring-urged by any suitable means, for example, by a coil spring located over the bolt and extending between the handle and gudgeon to normally urge the bolt downwardly.

In order to secure the fin to the gripping member, it is not necessary that such an operation be carried out while the boat is on shore, as the construction of the apparatus makes it possible for said operation to be carried out while the boat is floating in the water. It is only necessary to insert the flanged edge 18 of the fin into the T-shaped way and slide said fin forwardly until a desired position relative the longitudinal axis of the boat. The fin may then be moved slightly aft or forwardly to bring the nearest hole 25 in registry with the hole 38. The locking pin is then dropped through bore holes so as to restrain longitudinal sliding movement of said fin relative the gripping member. I

It is to be noted that when engaging the fin 13 with the gripping member 15, the foot portion 24 shall extend outwardly away from the center line of the boat. With both fins 13 and 14 arranged in the above manner, it will be seen that when the boat is at rest in the water, both fins will be immersed. When the boat moves forwardly, both the foot portion 24 of said fins 13 and 14 will act as planing surfaces and, if large enough, will lift the bottom of the boat clear of the surface of the water. The confining action of the vertical portions 23 of each of the fins will serve to prevent lateral displacement of the water therebetween and besides will serve to compress the air beneath the bottom of the boat and the surface of the water, said compressed air serving as an additional force to assist in raising the bottom thereof above said surface of the water.

It will also be seen that dependent upon the position of each of the fins relative to the chines of the boat and the length of each of the foot portions thereof, the fins will serve to stabilize the boat and prevent its skidding during turns and, by reason of the fact that it is longitudinally adjustable, the boat may be positioned so that, dependent upon the position of the center weight of the boat and the power of its engine, the weight of the boat may be distributed evenly throughout the length of the foot portion of each of the fins.

It is also to be noted that should it be desired to beach the boat or to load it on a trailer, the fins may easily be removed while the boat is in the water by reversing the procedure as outlined above.

In FIGURE 4 is illustrated another embodiment 50 of the fins. In this embodiment, each of the fins is bent along a longitudinal line adjacent the free edge of the foot portions 52 thereof to form an inwardly extending marginal tab portion 53, the angle between said tab portion and the foot portion being approximately 90. The provision of the tab further stabilizes the boat and provides a greater planing area for the fins.

What I claim as my invention is:

Hydro-foil attachment for boats comprising an elongated fin element' being bent along a longitudinal line forming a leg portion and a foot portion disposed at an obtuse angle with respect to each other, a transversely extending flange formed along the longitudinally extending free edge of the leg portion, said flange having a longitudinally aligned series of holes formed therethrough, an elongated fin gripping member to be fixedly secured in a fore and aft extending direction to the underside of the hull of a boat, said member having a longitudinally extending downwardly opening way formed therein, said way being adapted to slidably receive from its after end the flanged edge of the leg portion so as to hold the leg in an upright position, said fin gripping member extending at its after end beyond the transom of the boat and having a hole formed therethrough, said hole being aligned with a series of longitudinally aligned holes in the flange, and a fastening pin slidably insertable through the hole in the flange gripping member and any one of the holes in the flange so as to prevent longitudinal sliding movement of the fin relative to said gripping member.

References Cited by the Examiner FOREIGN PATENTS 3/1947 Italy. 3/1922 Germany. 

